Its been some time that administrators wanted a tool similar to the Exchange Remote connectivity Analyzer (EXRCA) to check for connectivity issues internally within their environment. Well, guess what? There is one available now, ready for you to download. Its called the Microsoft Connectivity Analyzer (MCA).
Please check the official product team's announcement here:
A point worth mentioning. This tool goes along with the already existing Microsoft Exchange Remote Connectivity Analyzer (EXRCA) which is also celebrating a new version release V2.1.
For some reason it had issues with Autodiscover on my internal domain.
To note, the email namespace is not the same as the domain name space.
External Autodiscover tests with EXRCA report no Autodiscover issues nor do any of my internal Outlook users.